LONDON - International experts called on Wednesday for greater cooperation to fight threats to computer networks but they differed on the definition of cyberterrorism, with a top British security official describing it as a "myth".

Estonian defense ministry official Christian-Marc Liflander said sustained electronic attacks on his country last year came both from crude hackers and from sophisticated "cyberterrorists" remotely manipulating zombie computers known as botnets.

"I would say we have entered an era of cyber terror and perhaps even of cyber war," Liflander told a London security conference at the Royal United Services Institute.

Estonia has said it believes the Russian government was behind last year's attacks, which came amid a diplomatic row over Tal

A recent Vista update is causing headaches for users with USB devices.

Microsoft last week re-released a software update intended to provide performance and reliability enhancements for Windows Vista -based and Windows Vista Service Pack 1-based systems. It was one of eight security bulletins and updates the company made available on April 8.

Users who installed the update, however, soon found their USB devices unresponsive, particularly mice and flash drives. Removing and re-installing the programs reportedly did not immediately solve the problem.

Microsoft confirmed the bug, but declined to provide further details.

"We are aware of concerns that a recent Microsoft update may be causing problems with USB devices," according to a Microsoft spokeswoman. "

WASHINGTON - Two consumer groups asked the Federal Trade Commission on Tuesday to create a "do not track list" that would allow computer users to bar advertisers from collecting information about them.

The Consumer Federation of America and the Consumers Union also urged the FTC to bar collection of health information and other sensitive data by companies that do business on the Internet unless a consumer consents.

The call echoed those of other privacy advocates who filed statements with the FTC on Internet companies' use of "behavioral advertising." That is the practice of tracking a computer user's activities online, including Web searches and sites visited, to target advertisements to the individual consumer.

In December, the FTC approved Google 's purchas

Editor's Note: Product not yet tested by editor. The following description is from the manufacturer.